Empiric monotherapy in neutropenia: a realistic goal?
Infection remains the major cause of morbidity and mortality for cancer patients who become granulocytopenic as a result of chemotherapy. Treatment is instituted at the first sign of infection and before the identification of the causative pathogen (empiric treatment). For many years, standard empiric treatment has been combination therapy with beta-lactams and aminoglycosides. The advent of new broad spectrum antibiotics, such as ceftazidime, has introduced the possibility of empiric monotherapy. However, ceftazidime has only modest activity against infections due to Gram-positive organisms, which presently account for at least 50% of infections in neutropenic patients, and resistance to ceftazidime in Gram-negative organisms has been documented. Meropenem is a new carbapenem with a broad antibacterial spectrum with greater in vitro activity than ceftazidime against staphylococci, streptococci and many Gram-negative bacteria. A comparative study of intravenous meropenem (1 g 8-hourly) and ceftazidime (2 g 8-hourly) in the empiric treatment of febrile neutropenic patients with haematological malignancies has been conducted. In an open, randomised trial of the treatment of 338 febrile episodes, all patients survived to 72 hours on both treatments, and meropenem was found to be at least as clinically effective as ceftazidime in eradicating both Gram-positive and Gram-negative infections. Early modification of treatment (48-72 hours) was required for approximately 40% of patients but occurred less frequently in patients treated with meropenem than with ceftazidime. Tolerability of both treatments was good. Meropenem should be compared with standard combination therapy in a large randomised trial before adopting it as empiric monotherapy for febrile neutropenic patients.